Lab Tests Are Important Tools

Having regular lab tests is a necessary part of caring for your health. If
you are living with HIV (HIV+), lab tests are especially important tools that
help you and your health care provider keep track of how you are doing in the
following areas:

The Basics

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When you are first diagnosed as HIV+ and when you first start taking HIV
drugs, you should get "baseline" tests that give a picture of your health at
that moment. Later tests can be compared against these results to see how
things are going, and if they are changing. Most lab tests should be done every
three to six months, or as often as your health care provider recommends.

Because different labs use different equipment, test results from different
labs can vary. Therefore, it is a good idea to have your tests done at the same
lab each time. If you get an unexpected result on one test, your health care
provider will probably want you to get a second test to see if the results are
the same as the first one. Try not to worry too much about a single unexpected
result -- usually trends over time are more important.

Most lab reports show the normal range of results from each test and
highlight any of your results that are outside the normal range. The ranges
listed below are general and may not be exactly the same as your lab. Look at
your lab report for the normal ranges they use.

Complete Blood Count (CBC)

Blood is made up of different types of cells including red blood cells,
white blood cells, and platelets. The complete blood count (CBC) is a test that
measures the amount of these cells in a sample of your blood. CBCs are
especially important for HIV+ people because some HIV drugs and infections can
cause changes in your red or white blood cell counts.

Red blood cells (erythrocytes)
Red blood cells (RBCs) carry oxygen throughout the body. A typical RBC count
for women is four to five million red blood cells. Hematocrit (HCT) measures
how much of your blood is made up of RBCs, and hemoglobin (HGB) tests measure
the amount of hemoglobin in your blood. Hemoglobin is the protein in RBCs that
allows them to carry oxygen. A normal HCT for women is 36 to 44 percent and a
normal HGB level is 12 to 15. A low RBC count, HCT, or HGB may mean you have
anemia, which can cause you to feel tired. For more information, see our Anemia and Women info sheet.

White blood cells (leukocytes)
White blood cells (WBCs) are produced by the immune system and help defend the
body against infection. A normal total WBC count is 4,500 to 10,000. A high
count may mean that your body is fighting an infection. Low counts may be
caused by certain drugs or infections. There are different types of white blood
cells that are listed on your lab report as "the differential." The
differential tells you the amount of each type of white blood cell as a
percentage of the total WBC count.

Neutrophils
These cells fight bacterial infections. A normal neutrophil percentage is about
50 to70 percent of the total WBC count. When your neutrophil count is low (a
condition called neutropenia), you are more likely to get bacterial
infections.

Lymphocytes
There are two types of lymphocytes: B cells and T cells. B cells make
antibodies and T cells attack germs. Usually, lymphocytes account for about 20
to 40 percent of the total number of WBCs. CD4 cells are a type of T cell that
is measured separately. For more information, see our sheet on Understanding CD4 Cells and CD4 Cell Tests.

Monocytes and
Macrophages
These cells engulf or "eat" and destroy disease-causing organisms (germs). They
normally make up about two to ten percent of the total WBC count.

Eosinophils and
Basophils
These cells play a role in allergic reactions and defend against parasites.
They normally make up about one to eight percent of the total WBC count.

Platelets (thrombocytes)
Platelets are necessary for blood clotting. A normal platelet count is about
130,000 to 440,000. If your platelet count is low, you may bleed or bruise
easily.

Blood Chemistry (Chemistry or Chem Screens)

Blood chemistry tests, also called chemistry or chem screens, measure
certain chemicals in your blood. Results of these tests give your health care
provider important information about your general health status, how well
organs like the liver and kidneys are working, and whether you may be
experiencing drug side effects. Abnormal results can indicate a problem that
needs to be addressed. Important blood chemistry tests include:

Liver functionThese tests help measure how well your liver is working. Some of the tests
measure liver enzymes such as alanine transaminase (ALT or SGPT), aspartate
transaminase (AST or SGOT), and alkaline phosphatase (ALP). High levels of
liver enzymes may be a sign of liver damage. Several HIV drugs can cause
elevated liver enzymes. Liver function tests also include bilirubin, which
comes from the breakdown of hemoglobin from RBCs. High levels of bilirubin may
indicate liver problems. Taking the HIV drug Reyataz (atazanavir) can increase
bilirubin levels. However, a rise in bilirubin due to taking Reyataz is
harmless.

Kidney functionThese tests help measure how well your kidneys are working. They include
blood urea nitrogen (BUN), creatinine, and uric acid. Kidney tests are
especially important if you are taking Viread (tenofovir).

ElectrolytesElectrolytes play important roles in the healthy functioning of cells,
nerves, and organs. Bicarbonate (CO2), chloride, potassium, and sodium are
electrolytes. Electrolyte imbalances may be caused by not getting enough
nutrients (malnutrition) or water (dehydration), or by kidney problems.

Blood sugar (glucose)
Your body uses glucose for energy. High glucose levels (hyperglycemia) can be a
sign of diabetes or insulin resistance (when the body does not respond to
insulin, a hormone produced by the pancreas to help control glucose levels).
High glucose levels can be a side effect of HIV drugs. Your health care
provider can monitor your levels through glucose tests. For the most accurate
results, it is best to check glucose levels when you have been fasting (not
eating or drinking anything but water for about eight hours). For more
information, see our Diabetes info sheet.

Blood fat (lipids)
Many HIV+ people have an increased amount of fat, or lipids, in their blood
such as cholesterol and triglycerides. Higher cholesterol levels can increase
the risk of a heart attack or stroke. Higher triglycerides can increase the
risk of damage to the pancreas (pancreatitis). Your lab report will list the
amount of the following lipids in your blood (for the most accurate results, it
is best to check lipid levels when you have been fasting):

Total cholesterol
Cholesterol is a fatty substance that circulates in the blood. It is best to
keep your total cholesterol level below 200.

Low-density lipoproteins
(LDL)
This is "bad" cholesterol, which can clog the arteries. It is best to keep your
LDL level below 100.

High-density lipoproteins
(HDL)
This is "good" cholesterol, which helps reduce the risk of heart disease. It is
best to get your HDL level up to at least 40.

Triglycerides
After eating, energy that is not needed right away is converted into a
substance called triglycerides, which is stored in fat cells. It is best to
keep your triglyceride level below 150.

Blood proteinsThese tests provide information on nutrition problems and help diagnose
kidney disease, liver disease, and many other conditions. Tests include albumin
and total protein.

Calcium
Calcium, one of the most important minerals in your body, is a major part of
bones and teeth. Blood calcium is tested to check for a range of conditions
relating to the bones, heart, nerves, kidneys, and teeth. It is important to
remember that you can still have weak bones (osteoporosis), even if your
calcium blood test is normal. For more information, see our info sheet on Bone Health.

Labs routinely group certain chem screen tests together and call them
panels. Some common panels you may see listed on your lab report are:

The Bottom Line

Since many HIV+ people have no noticeable symptoms of health problems, it is
important to get regular lab tests to monitor how you are doing. Abnormal blood
tests can be a sign of serious health problems and need to be addressed as soon
as possible so that you remain healthy and strong.

Whether you are taking HIV drugs or not, all the tests listed above are a
key part of your medical care. Regular monitoring is an important way to take
charge of your health.

This article was provided by The Well Project.
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